The first European artist to cross the equator, Camoes's narrative reflects the novelty and fascination of that original encounter with Africa, India and the Far East. The poem's twin symbols are the Cross and the Astrolabe, and its celebration of a turning point in mankind's knowledge of the world unites the old map of the heavens with the newly discovered terrain on earth. Yet it speaks powerfully, too, of the precariousness of power, and of the...